A series of benzofused sultams and fluorinated benzenesulfonamides were synthesized in superacid HF/SbF(5) from simple N-allylic derivatives. Almost all of these original compounds showed micromolar inhibitory activities against carbonic anhydrases I and II. The fluorinated derivatives inhibit better the tumor-associated isoforms IX and XII, and one of the tested compounds showed inhibition in the nanomolar range.

The synthesis of benzofused sultams and/or fluorinated sulfonamides, starting from N-allylic sulfonamides, was performed in superacid HF/SbF(5), through superelectrophilic activation. A dramatic effect of superacid composition on the selectivity of the reaction was shown and applied to the synthesis of cyclic 4-aminobenzenesulfonamides.

The first direct selective synthesis of novel gem-chlorofluorinated nitrogen-containing building blocks in superacid is reported. The dramatic role of the chlorine atom on the reaction is shown by in situ NMR experiments and allows the involvement of a novel original superelectrophilic activation process in superacid HF/SbF(5) to be postulated.